Camera bag upgrade - recommendations please?

At the moment I have a Lowepro Classified Sling 180 AW, and I love it. I love all the little pockets, the design is flawless, everything is easily accessible.

However, I just got a 70-200 f/4 IS, and suddenly things aren't so hot. The lens is too long to fit in the lens pocket - I can store it leaving the inside flap open and it doesn't jiggle around too much, but it's still more than I'd like. In addition, the bag is definitely not deep enough (wide, actually, if you look at it when worn on the back) to accomodate the lens mounted on a camera.

I'm thinking I need something a little wider or deeper, but still just as travel- and accessory- friendly. Any ideas?

Lowepro faskpack 350?

Looks very good but it has no weather flap and I'm going to need one - unless one can buy good, unobtrusive covers separately? And I'm really looking more for a backpack design this time, as the single strap was a strain sometimes at the end of a long trek, so the Slingshot 300 is out unfortunately...

The new Video Fastpack 350 has an AW cover included. Its a good bag for the price, I have the original version which is essentially the same in terms of ergonomics and storage.

The only problem with it is that it is very heavy when full loaded, and the padding/straps are not going to win any awards for design/comfort in that situation.

Toploader bags any good for you? I have 2 and use them almost exclusively. The big one can handle my 70-200, 50mm, and at least one more lens like 8-16 as well as 4 batteries, many cards, etc.

Lowepro Flipside 300.